1. Field of the Invention
The present invention relates to orthopedic prostheses and, more specifically, to provisional components used during orthopedic surgery to facilitate the selection of a permanent orthopedic prosthesis.
2. Description of the Related Art
The use of orthopedic implants to form artificial joints such as prosthetic knees is well known in the art. During a conventional surgical procedure to implant a prosthetic knee joint, a provisional femoral component and a provisional tibial component are placed on the distal femur and proximal tibia after resecting the distal femur and proximal tibia to confirm the proper size and position of the permanent femoral and tibial components. The provisional components typically come in a range of sizes which are identical in size and shape to the permanent components. The provisional components which are placed on the resected femur and tibia are typically selected after making a preliminary determination of the proper size. A trial reduction of the knee joint with the provisional components in place may indicate that the preliminary size determination was incorrect, that the gap between the femur and tibia is insufficient, or some other undesirable characteristic which requires the selection of a different sized tibial or femoral component thereby necessitating the further resection of either the tibia or femur.
Resection of the femur generally involves making three or four intersecting generally planar cuts and making changes to one such cut may require changes in the remaining cuts. The tibial plateau, on the other hand, generally only involves a single cut and provides a more convenient location for corrective actions. It is generally desirable to leave as much healthy bone stock as possible when implanting either total or partial prosthetic knee joints. It is particularly desirable to leave as much healthy bone stock as possible when implanting a unicompartmental or partial knee prosthesis which involves the removal of only a single condyle. This is due to the possibility that the remaining natural condyle may require replacement at a later date and leaving a greater amount of bone stock facilitates the later removal of the partial prosthetic joint and the implantation of a total prosthetic knee joint. Consequently, an improved system which facilitates the proper sizing, selection and positioning of the prosthetic components while minimizing the risk of having to conduct additional bone resections after a trial reduction of the initial provisional components would be desirable.